Implantable medical devices (IMDs) are used to treat patients suffering from a variety of conditions. Examples of INDs involving cardiac devices are implantable pacemakers and implantable cardioverter-defibrillators (ICDs). Such electronic medical devices generally monitor the electrical activity of the heart and provide electrical stimulation to one or more of the heart chambers, when necessary. For example, pacemakers are designed to sense arrhythmias, i.e., disturbances in heart rhythm, and in turn, provide appropriate electrical stimulation pulses, at a controlled rate, to selected chambers of the heart in order to correct the arrhythmias and restore the proper heart rhythm. The types of arrhythmias that may be detected and corrected by such IMDs include bradycardias (unusually slow heart rates), which can result in symptoms such as fatigue, dizziness, and fainting, and certain tachycardias (unusually fast heart rates), which can result in sudden cardiac death (SCD).
Implantable cardioverter-defibrillators (ICDs) also detect arrhythmias and provide appropriate electrical stimulation pulses to selected chambers of the heart to correct the abnormal heart rate. In contrast to pacemakers, however, an ICD can also provide pulses that are much stronger and less frequent. This is because ICDs are generally designed to correct fibrillation, which is a rapid, unsynchronized quivering of one or more heart chambers, and severe tachycardias, during which the heartbeats are very fast but coordinated. To correct such arrhythmias, ICDs deliver low, moderate, or high-energy shocks to the heart.
Generally, IMDs are designed to provide a telemetry function. As such, the IMDs are configured to automatically transmit and measure data from remote sources by wire or other means. Typically, IMDs are equipped with an on-board, volatile memory in which telemetered signals can be stored for later retrieval and analysis. In addition, a growing class of cardiac medical devices, including implantable heart failure monitors, implantable event monitors, cardiovascular monitors, and therapy devices, can be used to provide similar stored device information. Typically, the telemetered signals can provide patient physiologic and cardiac information. This information is generally recorded on a per heartbeat, binned average basis, or derived basis, and involve, for example, atrial electrical activity, ventricular electrical activity, minute ventilation, patient activity score, cardiac output score, mixed venous oxygen score, cardiovascular pressure measures, time of day, and any interventions and the relative success of such interventions. Telemetered signals can also be stored in a broader class of monitors and therapeutic devices for other areas of medicine, including metabolism, endocrinology, hematology, neurology, muscular disorders, gastroenterology, urology, ophthalmology, otolaryngology, orthopedics, and similar medical subspecialties.
Generally, upon detecting arrhythmias and, when necessary, providing corresponding therapies to correct such arrhythmias, the IMDs store the telemetered signals over a set period of time (usually before, during, and after the occurrence of such arrhythmic event). Subsequently, current practice in the art involves the use of an external programming unit, i.e., a programmer, for non-invasive communication with IMDs via uplink and downlink communication channels associated with the programmer. In accordance with conventional medical device programming systems, a programming head can be used for facilitating two-way communication between IMDs and the programmer. In many known implanted IMD systems, the programming head is positioned on the patient's body over the IMD side such that one or more antennae within the head can send RF signals to, and receive RF signals from, an antenna disposed within the hermetic enclosure of the IMD or disposed within the connector block of the IMD in accordance with common practice in the art.
Upon storing the telemetered signals within the programmers, such data can be subsequently analyzed by the patient's physician for diagnostic purposes. Previously, the data stored within the programmers was downloaded during visits to the physician; however, recent technology has enabled the patient to download such data at home using, for example, a personal computer (PC) and a network to transmit the data to the physician.
For patients who require the use of IMDs, it is quite commonplace for the patient to have episodes during which symptoms are experienced, e.g. shortness of breath, palpitations, dizziness, extreme tiredness, etc. However, in some cases, these episodes occur when the IMDs are not sensing an arrhythmia, and as such, no telemetered signals are stored with respect to such episodes. However, the physiologic and cardiac data that can be collected during these episodes can be of extreme importance to the physician, as conclusions can be made (upon analyzing such data) as to the patient's general quality of life and the suitability of the IMD with respect to the patient. As such, during and/or following such episodes, the patient may be instructed to keep a written account (e.g., a written diary) of symptoms experienced. As such, this written account can be analyzed by the physician when analyzing telemetered signals that may have been stored by the IMD to date. However, this task of providing a written account of the symptoms experienced has generally been found by the patient to be cumbersome and often not done. In turn, this lack of information complicates analysis by the physician of the stored data and/or clinical treatment of the patient.
The embodiments of the invention are directed to overcoming, or at least reducing the effects of, one or more of the limitations set forth above.